Monoprice MP Select Mini

When the Monoprice MP Select Mini 3D printer was released last year, it was a game changer. This was a printer for $200, yes, but it also held a not-so-obvious secret: a 3D printer controller board no one had ever seen before powered by a 32-bit ARM microcontroller with an ESP8266 handling the UI. This is a game-changing set of electronics in the world of 3D printing, and now, finally, someone is reverse engineering it.

[Robin] began the reverse engineering by attaching the lead of an oscilloscope to the serial line between the main controller and display controller. The baud rate is weird (500 kHz), but apart from that, the commands readily appear in human-parsable text. There is a web server built into the MP Mini printer, and after inspecting the web page that’s served up from this printer, [Robin] found it was possible to send G-code directly from the controller board, get a list of files on the SD card, and do everything you would want to do with a 3D printer.

After deconstructing the circuit on the display board, [Robin] found exactly what you would expect from such a simple board: an SPI display driven by an ESP, and a big flash chip sitting off to the side. [Robin] found the the model of the display, and quickly built a project on Platform.io to draw text to the LCD. This isn’t the end of the project – there’s still a lot that must be done before this printer is squirting out parts with custom firmware.

While this isn’t a hack of the driver board inside the MP Mini, that’s not really a problem. The motor driver board in this printer doesn’t really need any changes, and was already ahead of its time when this printer was released last year. As with most things, the UI is the weak point, and upgrading the firmware and built-in web server for this printer is the best way forward.

[Robin] put together a truly phenomenal video of how he reverse engineered this display controller. You can check that out below.

Around this time last year, Monoprice quietly unveiled a small, $200 3D printer. At the time, a fully functioning printer at this price point wasn’t unheard of. A good 3D printer at this price point was. It turned out this printer was actually fantastic and completely changed the value proposition of desktop 3D printers.

In the year since the release of the MP Select Mini printer, Monoprice has been hard at work bringing costs down, reworking designs, and creating an even less expensive printer. Now, it’s out. It’s available for pre-order on Indiegogo right now. Is this still a $150 printer? Not quite: the ‘early bird’ price is $159 with free shipping and August delivery, and a regular price of $169 plus $10 shipping with September or October delivery. There’s also a bundle for $279 that includes the printer, 2kg of filament, and a software package.

The first time we saw this tiny printer was way back in January at CES. It looked to be an extremely capable printer; the only question was if Monoprice could produce it and get it out the door. This would be a tall order; this printer comes with NEMA 17 stepper motors, a heated bed, a 32-bit controller board, and has WiFi enabled.

Here’s what we know about the capabilities of this printer. It’s a fairly standard delta printer with Bowden extruder and a heated bed. PLA and ABS is supported. The printer has auto bed leveling that measures the bed by ‘tapping’ the nozzle against the bed in about a dozen places before printing. From what we saw at CES, the hot end appears similar to the first revision of the $200 MP Select Mini — possibly opening up the door to E3D hot end installations.

Is this printer worth it? Every 3D printer released on a crowdfunding platform should come with the standard warnings, but Monoprice says this machine is in production right now. This raises the question: why release it on Indiegogo when Monoprice already has the whole ‘taking orders for products online’ thing in the bag? I suspect this crowdfunding campaign is just building a buffer; a year ago, the MP Select Mini was perpetually out of stock, and demand far outstripped supply. The same thing will happen with a 3D printer that’s even deeper into impulse buy territory.

In any event, the printer we’ve all been waiting for has been ‘released’, for varying values of ‘released’. The first units will start making their way onto desktops this summer, and we’re going to pick one up and put it through its paces. You can check out Monoprice’s video of this printer below.

We’ve had a love affair with the Monoprice Select Mini since it came out. The cheap printer has its flaws, though. One of them is that the controller is a bit opaque. On the one hand, it is impressive that it is a 32-bit board with an LCD. On the other hand, we have no way to modify it easily other than loading the ready-built binaries. Want to add bed leveling? Multiple fans? A second extruder and mixing head? Good luck, since the board doesn’t support any of those things. [mfink70] decided the controller had to go, so he upgraded his Mini with a Smoothie board.

On the plus side, the Smoothie board is also a 32-bit board with plenty of power and expansion capability. On the downside, it costs about half as much as the printer does. Just replacing the board was only part of the battle. [mfink70] had to worry about the steppers, the end stops, and a few other odds and ends.

2016 is the year of the consumer 3D printer. Yes, the hype over 3D printing has died down since 2012. There were too many 3D printers at Maker Faire three years ago. Nevertheless, sales of 3D printers have never been stronger, the industry is growing, and the low-end machines are getting very, very good.

Printers are also getting cheap. At CES last January, Monoprice, the same company you buy Ethernet and HDMI cables from, introduced a line of 3D printers that would be released this year. While the $300 resin-based printer has been canned, Monoprice has released their MP Select Mini 3D printer for $200. This printer appeared on Monoprice late last month.

My curiosity was worth more than $200, so Hackaday readers get a review of the MP Select Mini 3D printer. The bottom line? There are some problems with this printer, but nothing that wouldn’t be found in printers that cost three times as much. This is a game-changing machine, and proof 2016 is the year of the entry-level consumer 3D printer.